The present invention relates to a wrapper for two different foods such as a mass of compressed rice and a dried seaweed sheet. The so-called ONIGIRI shown in FIG. 1, formed of a mass of rice 9 compressed by hand or in a mold and having usually an approximately triangular shape, is a convenient food typically consumed as a snack or for a picnic, however, since the mass of rice by itself tastes too plain, a dried seaweed sheet 8 is usually applied to cover this mass of rice to improve the taste. In producing this kind of mass of compressed rice with a dried seaweed wrapping therearound, a certain amount of rice is fed into a mold of triangular, circular or rectangular shape to form a mass of compressed rice of the desired shape, and then a dried seaweed sheet 8 is applied to wrap the mass of compressed rice 9 to produce a final product.
Thereafter the mass of rice 9 produced by this method is wrapped with an appropriate food wrapping synthetic resin sheet such as polyethylene, polypropylene, or the like for sale to consumers. In the prior processes for producing a mass of rice, the productivity rate for forming the mass of rice itself is relatively high; however, the wrapping process totally depends upon manual handling such as inserting the mass of rice into an envelope and closing the envelope to seal the mass of rice. Therefore, problems such as decreased in productivity or crumbling of the formed shape owing to the complexity of the wrapping process are encountered. Moreover, sanitary problems caused by manual handling, or difficulty in breaking open the envelope at serving also arise. In order to overcome these problems, several wrappings for a seaweed covered mass of rice has been proposed.
In Japanese Utility Model publication No. 57-10542, for example, a wrapping for producing a seaweed covered mass of rice is disclosed which comprises an inner triangular bag containing a mass of rice therein and having an opening thereatop, and an outer triangular bag of synthetic resin sheet for containing this inner triangular bag therein and provided with a cut-way opening through which the inner triangular bag is to be pulled out. On the other hand, in Japanese Utility Model publication No. 57-42318, there is described a wrapping for producing a dried seaweed covered mass of rice using an inner triangular bag provided with a slit which can be pulled out of the top opening of an outer triangular bag.
In the known wrappings, however, the top end of the outer envelope is completely open to the air so that it does not solve the problem as seen in the prior art that the dried seaweed sheet becomes moistened by air entering through the top end of the bag and loses its relish or taste.
In both prior art wrapping instruments, in addition to the serious defect that an apparent opening exists in either the outer or inner bags, the closure of the upper openings of the outer and inner triangular bags is rudimentary and sealing incomplete. The methods employed consist of folding the flaps one upon another and closing them by a seal member, so that they can not achieve the purpose of sealing the food therein.
Therefore, these prior art wrappings present a serious sanitary defect in that they cannot prevent contamination as by bacteria, or infiltration by moisture, insects or dust owing to the incompleteness of sealing. Moreover, there is the further problem that, because of incomplete sealing of the inner triangular bag, the moisture of the mass of rice may affect or damage the relish or taste of the dried seaweed. Furthermore, in the wrappings using these kinds of bags, the operation for inserting the mass of rice into the bag is a manual handling so that these known wrapper instruments are not suitable for a mass production system. The object of the present invention is to provide a new wrapping for a seaweed covered mass-of-rice which overcomes the above-mentioned defects. Another object of this invention is to provide a new, inexpensive wrapper for a seaweed covered mass-of-rice offering easy handling and good sanitary preservation.